SIRT1 protein, a member of Silent Information Regulator 2 (Sir2) protein family, have gained considerable attention as epigenetic regulators for a great area in the human physiology. Changes in sirtuin expression are critical in several diseases, including metabolic syndrome, cardiovascular diseases, cancer and neurodegeneration. Here, we provide an overview of the association of the increasing level of SIRT1 protein for regulating some disease related conditions such as obesity, cardiovascular diseases and neurodegeneration. This review also provides a detailed molecular understanding of the interaction of the some basic molecules with increasing SIRT1 levels rather than reduction of the SIRT1 expression. In this context, the current approaches to enhancing the expression of SIRT1 points the importance of epigenetics in several age-related diseases to provide a healthy aging by developing novel therapies which can prevent or damp the progression of some diseases.

Increased serum insulin levels and reduced peripheral insulin activities seen in insulin resistance syndrome are associated with age-dependent cognitive impairment and Sporadic Alzheimer's Disease (SAD), suggesting a disturbance in the insulin signalling system in the brain and possibly being one of the causes of dementia. Therefore, the streptozotocin (STZ)-induced animal may be an appropriate model for the investigation of SAD and related dementia. This study was designed to investigate the beneficial effect of Curcumin (CUR), a neuroprotective agent, on intracerebroventricular (ICV) STZ-induced cognitive impairment in rats. For this purpose, adult male Wistar rats were bilaterally ICV injected with STZ (3 mg/kg). An artificial cerebrospinal fluid (aCSF) was given to the control group (SHAM) instead of STZ on days 1 and 3. Learning and memory performance were assessed using the "passive avoidance task" and the "Morris water maze test". After confirmation of acquisition impairment with these tests, the STZ group was divided into two subgroups: STZ+ vehicle (Vh) and STZ+CUR. The rats in the SHAM and STZ+Vh groups were administered intraperitoneally with 0.5 ml Vh and the rats in the STZ+CUR group were treated intraperitoneally with CUR (300 mg kg −1 day −1 in Vh) for 10 days starting from the 25th day after STZ injection. The Morris water maze test was reapplied on the 35th day after STZ injection and all of the rats were sacrificed on day 36 for quantitation of IGF-1 and for histopathological evaluation. Rats in the STZ+CUR group were found to have a higher performance in cognitive tests than rats in the STZ+Vh group (P<0.01). In parallel with the cognitive tests, IGF-1 levels were decreased in all of the STZ-injected groups (1.78±0.34) compared to the SHAM group (3.46±0.41). In contrast, CUR treatment significantly increased IGF-1 levels (P<0.001). The degree of neuronal loss decreased after CUR treatment compared to the SHAM group (P< 0.02). These results clearly indicate that CUR treatment is effective in reducing the cognitive impairment caused AGE

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We report a case of progressive spastic paraparesis in a 45-year-old man with total portal-systemic shunting, which developed spontaneously due to congenital hepatic fibrosis. Cellular functions of the liver, except for an elevated blood ammonia level, were within normal limits, as is usual in congenital hepatic fibrosis. This case shows that spastic paraparesis following portal-systemic shunting may occur without liver failure.

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These findings suggest that TQ has an enhancing effect on cell survival and neurogenesis in healthy hippocampus, rather inducing apoptosis in damaged neurons. This may proceed via ERK/JNK and CREB signaling pathways as a candidate acting mechanism for TQ.

In this study, we investigated the protective effects of angiotensin IV (Ang IV) on cognitive function in streptozotocin (STZ)-induced diabetic rats. Male Wistar albino rats, were randomly divided into four groups; control (C), diabetes (Dia, 60 mg/kg, STZ, i.p.), Ang IV (5 µg/kg, s.c.) and Dia+Ang IV. The passive avoidance and Morris water maze (MWM) tests were used to evaluate learning and memory performance. Behavioral tests were carried out between 21 and 30 days after the initial Ang IV injection. Hippocampi were dissected and retained for biochemical and Western blot analysis. The Dia group exhibited the poorest behavioral results, while the Dia+Ang IV group performed highest on the MWM task. Superoxide dismutase, glutathione peroxidase, and malondialdehyde levels increased significantly in the Dia group compared to Dia+Ang IV. Brain-derived neurotrophic factor (BDNF) and N-methyl-D-aspartate levels were significantly elevated, while levels of GABAA significantly decreased, in the Dia+Ang IV group compared to the Dia group. These findings suggest that peripheral administration of Ang IV ameliorated spatial memory in diabetic rats by decreasing hippocampal oxidative stress and BDNF levels.

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